Lightning arrestor assembly



June 2, 1970 QLE GUTSI -IAL L 3,515,948

LIGHTNING ARRESTOR ASSEMBLY Filed'June 20, 1968' I United States Patent3,515,948 LIGHTNING ARRESTOR ASSEMBLY Charles Edward Gutshall, Roselle,Ill., assignor to Illinois Tool Works Inc., Chicago, lll., a corporationof Delaware Filed June 20, 1968, Ser. No. 738,673 Int. Cl. H02h 1/04,3/22 US. Cl. 317-61 11 Claims ABSTRACT OF THE DISCLOSURE This inventionrelates generally to lightning arrestor apparatus and more particularlyto a lightning arrestor assembly for use with a television or the likeantenna.

Radio and television antennas which extend upwardly from the roofs ofbuildings, or the like, are, during storms, often struck by lightning. Ahigh voltage surge resulting from the lightning bolt may cause damage toa television or radio set connected to the antenna if the latter is notgrounded.

While conventional lightning arrestors used to prevent the above are,for the most part, satisfactory in operation, they are usually complexin construction. The arrestors generally include an element which iscaused to break down when the antenna is subjected to a lightning surge.Once used however, many of the arrestors of this type may not be reused,or in the event they are reusable, the element must be replaced therein.

Accordingly, it is a primary object of this invention to provide a newand improved lightning arrestor assembly which is simple in constructionand use, and relatively inexpensive to produce.

It is still another object of the present invention to provide alightning arrestor assembly of the last mentioned type which may bereused without replacing component parts thereof.

It is a further object of the present invention to provide a lightningarrestor assembly for connection to an antenna lead-in wire whichutilizes the break down of the partially penetrated insulation of thewire to ground the antenna in the event of lightning striking thelatter.

It is yet another object of this invention to provide a novel terminalnut member for use in a lightning arrestor assembly of theabovementioned type, having a plurality of nibs on one face thereof of apredetermined height for partially piercing the insulation of an antennalead-in wire.

A better understanding of the present invention and its organization andconstruction may be had by referring to the description below inconjunction with the accompanying drawings, wherein:

FIG. 1 is a perspective view of an antenna mounted on a building andcoupled to a lightning arrestor assembly according to the invention;

FIG. 2 is an enlarged perspective view of the lightning arrestorassembly of FIG. 1;

FIG. 3 is a side sectional view of the lightning arrestor Patented June2, 1970 assembly of FIG. 2 taken along the line 33 thereof;

FIG. 4 is a bottom plan view of the lightning arrestor assembly of FIG.3;

FIG. 5 is an enalarged side view of the terminal nut used in thelightning arrestor assembly of FIG 3;

5 Hg. 6 is a top plan view of the terminal nut of FIG.

FIG. 7 is an enlarged, side fragmentary sectional view of the terminalnut and top retaining nut and clamp washer arrangement mounted on theterminal of a lightning arrestor assembly according to the invention,illustrating the manner in which the aforementioned are employed tosecure an antenna lead wire therebetween.

Referring now to the drawings in greater detail, FIG. 1 thereof shows atelevision antenna 10 mounted on a chimney 12 of a building 14. Thetelevision lead-in wire 16, which is of the conventional fiat orelliptical cross-sectional shaped twin lead, or other suitable typeextends from the antenna along wall 18 of the building and through anaperture 20 provided in the wall to a television set (not shown) withinthe building.

A lightning arrestor assembly 22 is mounted on the Wall 18 of thebuilding and is coupled to the antenna lead-in wire. The assembly 22 isconnected to a grounded water pipe 25 or the like, within the buildingby an insulated conductor wire 24.

The lightning arrestor assembly 22 according to the invention (FIGS.2-4) comprises a base 26 of Bakelite or other suitable insulatingmaterial. The base is cupshaped with a circular, flat bottom surface 28,a smaller, fiat top surface 30 and an inclined sidewall 32 whichinterconnects the bottom and top surfaces.

A terminal stud or bolt 34 of an electrically conductive material suchas, for example, steel, is mounted in a central aperture 36 providedthrough base 26 and extending from the bottom to the top surfacesthereof. The terminal includes a specially shaped base portion 38 whichis fitted into a complementarily shaped pocket 40 formed in the base 26within a concentrically shaped cavity 42 which extends into the bottomsurface 28 of the base 26. The terminal stud 34 is prevented fromrotation by the insertion of base portion 38 thereof into pocket 40 andincludes an opening 36 extending thereinto through base portion 38 forreceiving a plug 37 connected by means of wire 24 to ground. The studterminal 34 is of a length suflicient to extend through base 26 so thatthe opposite threaded end 44 thereof extends outwardly therefrom.

An electrically conductive steel terminal nut 46 (FIGS. 5 and 6)including a first relatively flat face 48 is screwed onto the threadedend 44 of stud 34 (FIG. 3) and is tightened so that face 48 thereof isseated on the top surface 30 of the base 26. The tightening of the nutfastens stud 34 securely to base 26. The nut 46 has a twelve sided outeredge 50 so that 12-point drive equipment is required to remove the nutfrom the threaded stud. This prevents tampering therewith in most cases.

The opposite, outwardly extending face 52 of the terminal nut includes,formed thereon, a plurality of nibs, each designated by the numeral 54.The nibs extend outwardly from face 52 of the nut a predetermineddistance, approximately one-quarter of an inch when used withconventional antenna wire and have a cutting edge 56 (FIG. 7) forpiercing or penetrating the insulation 58 of the wire.

An internally toothed clamp washer 60 and a retaining hex nut 62, bothof a Well-known type, are mounted on the threaded end 44 of studterminal 34 in opposing relation to face 52 of nut 46. Nut 62 istightened downwardly on the threaded end 44 of the stud 34 forcing theclamp washer into engagement with the lead-in wire 16 thereby tosandwich the wire between the nibbed face 52 of the terminal nut 46 andthe clamping washer 60. This causes nibs 54 to pierce the insulation 58of wire 16 as shown in FIG. 7. It should be noted that the nibs do notextend through the insulation to make contact with the conductors 64therein. While a clamp washer and retaining nut have been shown in thedrawings, it is to be understood that other suitable retaining membersor arrangements may be employed, if desired.

For purposes of affording a more complete understanding of theinvention, it is advantageous now to provide a functional description ofthe mode in which the component parts thus far described cooperate.

To assemble the lightning arrestor assembly according to the invention,threaded end 44 of terminal 34 is inserted into aperture 36 throughcavity 42 in the bottom surface of base 26. The specially shaped baseportion 38 of the terminal is received in pocket 40 therein to preventturning of the terminal in the aperture 36. Next, the steel terminal nut46 is tightened onto threaded end 44 of terminal 34 until the flatsurface 48 of the nut abuts surface 30 of base 26. This serves to holdthe terminal 34 on base 26 and to make an electrically conductiveconnection therebetween.

At this time, the base 26 may be mounted by means of screws, such as 68,on a building wall 18, the bottom surface 28 of the base abutting thewall. The base should be mounted closely adjacent the television or thelike lead-in wire 16, as shown in FIG. 1. A ground lead 24 is thenconnected to the base portion 40 of stud terminal 34, either in themanner illustrated (i.e. with a plug 37 being inserted into an aperture35 in the terminal 34) or by some suitable alternate means.

After the aforementioned has been completed, the lead-in wire 16 to theantenna (FIG. 1) is placed in contact with surface 52 of terminal nut 46so as to rest on nibs 54. If the wire 16 is of the flat twin lead typeas shown in FIG. 2, it is placed with one of the flat surfaces thereofresting against the nibbed surface 52 of terminal nut 46. If, however,the lead-in wire is elliptical in cross-section, it may be wrappedpartially about terminal 34 instead. A clamp washer 60 is placed on thethreaded end 44 of stud 34 and a retaining nut 62 is mounted on theterminal end and tightened downwardly therealong. As the nut 62 istightened, lead-ir1 wire 16 is squeezed between clamp .washer 60 andnibs 54, the wire being retained in position thereby. The nibs 54 arecaused to pierce the insulation of wire 16 (FIG. 7) until they moveclosely to conductors 64 therein, but without making mechanical orelectrical contact therewith. This prevents the grounding of the lead-inwire under normal conditions but weakens the insulation at the points ofpenetration. The nibs also provide strain relief to the wire and serveas means for preventing radial movement of the wire during tightening(i.e. the wire is prevented from spreading laterally when compressedunder the nut or clamp).

If after the aforementioned mounting procedure is completed the antennashould be struck by lightning, the current produced by the lightningsurge will travel along conductors 64 of wire 16 reaching the points ofpenetration by nibs 54. Because of the piercing relation of nibs 54 andthe insulation of wire 16 nearly to conductors 64 thereof, there is, asmentioned heretofore, a weakening at those points along the wire. Thecurrent produced by the lightning causes a burning of the weakenedinsulation to complete a path between the conductors 64 of the wire andterminal nut 46. This in turn channels the lightning surge to groundthrough the terminal 34 and ground lead 24 connected thereto, preventingdamage from the lightning to a television or the like set connected atthe end of lead wire 16. Little, if any, damage to the lightningarrestor assembly will occur. Consequently, no replacement of componentsis necessary for reuse of the arrestor assembly.

Thus, the assembly provides a simple, effective and easy to uselightning arrestor which provides ample protection from lightning andwhich is reuseable without requiring a substitution or addition ofcomponents.

While a particular embodiment of the invention has been shown anddescribed, it should be understood that the invention is not limitedthereto since many modifications may be made. It is thereforecontemplated to cover by the present application any and all suchmodifications as fall within the true spirit and scope of the appendedclaims.

What is claimed is:

1. A lightning arrestor assembly for use with a wired antenna or thelike, comprising: a base member of insulating material, a terminalmounted on said base member, at least one end of said terminal extendingoutwardly from said base member, said terminal being connected toground, a member of electrically conductive material mounted on said oneterminal end, a first surface of said member including a plurality ofprotrusions extending outwardly therefrom a predetermined distance, andclamping means mounted on said one terminal end, said clamping meansbeing movable along said terminal end to a position adjacent theprotrusions of said member for securing therebetween the wire of saidantenna, whereby said protrusions are penetratable partially into theinsulation of said wire without making contact with the conductorsthereof.

2. A lightning arrestor assembly as claimed in claim 1 wherein said oneend of said terminal is threaded, wherein said clamping means includes anut having complementary threads, thereby to be movable along saidterminal end toward and away from said member, and wherein saidprotrusions comprise nibs of a predetermined size formed on said firstsurface of said member.

3. A lightning arrestor assembly as claimed in claim 2 wherein saidterminal comprises a threaded bolt, wherein said base includes anaperture extending therethrough, wherein said bolt extends through saidaperture in said base with the threaded end of said bolt extendingoutwardly from one end thereof and wherein said member includes acomplementarily threaded nut having on one surface thereof esaidplurality of nibs, said nut being tightened onto said threaded bolt withsaid nibbed surface extending outwardly from said base, said nut holdingsaid terminal bolt onto said base.

4. A lightning arrestor assembly as claimed in claim 2 wherein saidclamping means further includes a clamp washer, which upon tighteningthe nut of said clamping means onto said threaded terminal end engagessaid antenna wire.

5. A lightning arrestor assembly as claimed in claim 3 wherein saidantenna wire is relatively fiat and includes a pair of spaced apartinsulated conductors, the insulation about said conductors beingslightly greater in depth than the outwardly extending predetermineddistance of said nibs from the first surface of said nut.

6. A lightning arrestor assembly as claimed in claim 3 wherein saidantenna wire is elliptical in cross section and includes a pair ofconductors mounted in a predetermined thickness of insulation, andwherein the distance the nibs extend from the first surface of said nutis slightly less than the thickness of said insulation, thereby to causesaid nibs to penetrate the latter without making contact with saidconductors.

7. A lightning arrestor assembly for connection to the insulated lead-inwire of an antenna or the like, comprising: a base of insulatingmaterial for mounting on a support surface, an electrically conductiveterminal mounted on said base and having a threaded end thereofextending outwardly therefrom, said terminal being grounded, a firstcomplementarily threaded terminal nut member being mounted on saidthreaded end of said terminal, a first one of the surfaces of said firstnut member including a plurality of nibs extending outwardly apredetermined distance therefrom, and a second complementarily threadedterminal nut member mounted on the threaded end of said terminal with asurface thereof facing toward the outwardly extending nibs of said firstnut member, said nut members, upon tightening either or both thereof,being movable toward each other for securing therebetween the lead-inwire of said antenna, there-by to cause said nibs to penetrate theinsulation of said wire while not making contact with said conductorportion thereof.

8. A lightning arrestor assembly as claimed in claim 7 wherein said baseincludes an aperture extending therethrough with a predeterminedlyshaped cavity in one surface thereof communicating with said aperture,wherein said terminal includes a threaded bolt member having on one endthereof a head having a shape complementary to that of said cavity forreceipt therein, said bolt member extending through said base on saidaperture, the opposite, threaded end of said bolt member extendingoutwardly from the opposite surface of said base, and wherein one ofsaid nut members is tightened onto said threaded end to secure saidterminal bolt member on said base.

9. A lightning arrestor assembly as claimed in claim 8 wherein said onenut member securing said bolt member to said base is said first nutmember, the nibs thereof extending outwardly therefrom away from saidbase.

10. A terminal nut member for use in a lightning arrestor arrangementincluding an insulated lead-in Wire having a predetermined number ofconductors with a predetermined thickness of insulation thereabout, abase of insulating material, a grounded, threaded terminal extendingoutwardly from said base and a retaining nut mounted on said terminal;said terminal nut member including on a first surface thereof aplurality of nibs, said nibs extending outwardly from said first surfacea distance slightly less than the thickness of said insulation aboutsaid conductors, said terminal nut member for mounting on said terminalwith said nibbed surface facing one of the surfaces of said retainingnut so that upon the tightening of either or both of said nuts formovement along said threaded terminal said lead-in wire may be securedtherebetween, thereby to cause said nibs to pierce said insulation toweaken the latter without contacting said conductors.

11. A terminal nut member as claimed in claim 10 wherein the edgethereof is twelve sided and wherein the surface thereof opposite saidnibbed surface is relatively flat for securing said nut member againstsaid base.

References Cited UNITED STATES PATENTS 2,654,857 10/1953 Finkel 3l7--692,666,908 1/ 1954 Klostermann 31769 3,312,868 4/1967 Vodicka 3l761 J DMILLER, Primary Examiner H. FENDELMAN, Assistant Examiner

